Mechanics

CHEVROLET TRUCK SPARK PROBLEM

1990 Chevrolet Truck

5.7 liter truck stalls when cold. Continues to stall and lack power until warmed up. Then it runs fine after it's warmed up. Any help would be appreciated.
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Craig moore
November 16, 2012.




Check to see if you are getting the proper spark, take a spark plug out, attach the spark plug wire, and hold the threads of the spark plug against the engine block and have somebody turn it over a few revolutions, looks for bright blue or white colored spark, do this with all of them and report back with the results
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Tiny
Papajohnslice
Nov 16, 2012.
Is it carb or fuel injected? Because there is a possibility that it's not getting enough air until the air intake is opened up

Tiny
Papajohnslice
Nov 16, 2012.
Fuel injected

Tiny
Craig moore
Nov 16, 2012.
I'm thinking iac valve

Tiny
Craig moore
Nov 16, 2012.
On tbi units they had aproblem of blowing the gasket under them, check for that as well as soft hoses goign to pcv and map sensor on firewall. If those are soft replace them spray chooke cleaner under the tbi to check for leak if rpm change then you've found the leak. If it continues to do that after these fixes, then check fuel pressure which shold be 9-11psi. Also if the question is not answered by an expert they could lead you ln the wrong direction. You can also clean iac with choke cleaner but do not remove it.

Hmac300
Nov 16, 2012.

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